Normally in Gulp tasks look like this:

gulp.task('my-task', function() {
    return gulp.src(options.SCSS_SOURCE)
        .pipe(sass({style:'nested'}))
        .pipe(autoprefixer('last 10 version'))
        .pipe(concat('style.css'))
        .pipe(gulp.dest(options.SCSS_DEST));
});

Is it possible to pass a command line flag to gulp (that's not a task) and have it run tasks conditionally based on that? For instance

$ gulp my-task -a 1

And then in my gulpfile.js:

gulp.task('my-task', function() {
        if (a == 1) {
            var source = options.SCSS_SOURCE;
        } else {
            var source = options.OTHER_SOURCE;
        }
        return gulp.src(source)
            .pipe(sass({style:'nested'}))
            .pipe(autoprefixer('last 10 version'))
            .pipe(concat('style.css'))
            .pipe(gulp.dest(options.SCSS_DEST));
});

---

Gulp doesn't offer any kind of util for that, but you can use one of the many command args parsers. I like yargs . Should be:

var argv = require('yargs').argv;

gulp.task('my-task', function() {
    return gulp.src(argv.a == 1 ? options.SCSS_SOURCE : options.OTHER_SOURCE)
        .pipe(sass({style:'nested'}))
        .pipe(autoprefixer('last 10 version'))
        .pipe(concat('style.css'))
        .pipe(gulp.dest(options.SCSS_DEST));
});

You can also combine it with gulp-if to conditionally pipe the stream, very useful for dev vs. prod building:

var argv = require('yargs').argv,
    gulpif = require('gulp-if'),
    rename = require('gulp-rename'),
    uglify = require('gulp-uglify');

gulp.task('my-js-task', function() {
  gulp.src('src/**/*.js')
    .pipe(concat('out.js'))
    .pipe(gulpif(argv.production, uglify()))
    .pipe(gulpif(argv.production, rename({suffix: '.min'})))
    .pipe(gulp.dest('dist/'));
});

And call with gulp my-js-task or gulp my-js-task --production .

---

In my project I use the following flag:

gulp styles --theme literature

Gulp offers an object gulp.env for that. It's deprecated in newer versions, so you must use gulp-util for that. The tasks looks like this:

var util = require('gulp-util');

gulp.task('styles', function() {
  return gulp.src(['src/styles/' + (util.env.theme ? util.env.theme : 'main') + '.scss'])
    .pipe(compass({
        config_file: './config.rb',
        sass   : 'src/styles',
        css    : 'dist/styles',
        style  : 'expanded'

    }))
    .pipe(autoprefixer('last 2 version', 'safari 5', 'ie 8', 'ie 9', 'ff 17', 'opera 12.1', 'ios 6', 'android 4'))
    .pipe(livereload(server))
    .pipe(gulp.dest('dist/styles'))
    .pipe(notify({ message: 'Styles task complete' }));
});

The environment setting is available during all subtasks. So I can use this flag on the watch task too:

gulp watch --theme literature

And my styles task also works.

Ciao Ralf

---

Here's a quick recipe I found:

gulpfile.js

var gulp   = require('gulp');

// npm install gulp yargs gulp-if gulp-uglify
var args   = require('yargs').argv;
var gulpif = require('gulp-if');
var uglify = require('gulp-uglify');

var isProduction = args.env === 'production';

gulp.task('scripts', function() {
  return gulp.src('**/*.js')
    .pipe(gulpif(isProduction, uglify())) // only minify if production
    .pipe(gulp.dest('dist'));
});

CLI

gulp scripts --env production

Original Ref (not available anymore): https://github.com/gulpjs/gulp/blob/master/docs/recipes/pass-params-from-cli.md

Alternative with minimist

From Updated Ref: https://github.com/gulpjs/gulp/blob/master/docs/recipes/pass-arguments-from-cli.md

gulpfile.js

// npm install --save-dev gulp gulp-if gulp-uglify minimist

var gulp = require('gulp');
var gulpif = require('gulp-if');
var uglify = require('gulp-uglify');

var minimist = require('minimist');

var knownOptions = {
  string: 'env',
  default: { env: process.env.NODE_ENV || 'production' }
};

var options = minimist(process.argv.slice(2), knownOptions);

gulp.task('scripts', function() {
  return gulp.src('**/*.js')
    .pipe(gulpif(options.env === 'production', uglify())) // only minify if production
    .pipe(gulp.dest('dist'));
});

CLI

gulp scripts --env production

链接地址: http://www.djcxy.com/p/95310.html

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